The present invention relates to an apparatus for the separation of magnetic constituents from a dispersion comprising these magnetic constituents and nonmagnetic constituents, comprising at least one loop-like canal through which a dispersion flows having at least two inlets and at least two outlets, further comprising at least one magnet that is moveable alongside the canal, wherein the canal is arranged relative to gravity in a way that nonmagnetic constituents are assisted to go into at least the one first outlet (stream I) by sedimentation and by the current of the dispersion and magnetic constituents are forced into at least one second outlet (stream II) by magnetic force against a current of flushing water. Furthermore, the present invention relates to a process for the separation of magnetic constituents from a dispersion comprising these magnetic constituents and nonmagnetic constituents, wherein this dispersion flows through at least one loop-like canal having at least two inlets and at least two outlets, further comprising at least one magnet that is moveable alongside the canal, wherein the canal is arranged relative to gravity in a way that, nonmagnetic constituents are assisted to go into the at least one first outlet by sedimentation and by the current of the dispersion and magnetic constituents are forced into at least one second outlet by magnetic force against a current of flushing water. In addition, the present invention relates to the use of an apparatus as mentioned above for separating magnetic constituents from a dispersion comprising these magnetic constituents and nonmagnetic constituents.
Processes and apparatuses for the separation of magnetic constituents from a dispersion comprising these and nonmagnetic constituents are already known to the skilled artisan.
WO 2010/031617 A1 discloses a device for separating ferromagnetic particles from a suspension, wherein this device comprises a tubular reactor and a plurality of magnets which are arranged outside the reactor, the magnets being moveable along at least a part of the length of the reactor up to the vicinity of a particle extractor by means of rotary conveyor. The canal is a linear tube and is not loop-like. The cleaning of the magnetic fraction is not described.
U.S. Pat. No. 6,149,014 discloses a mill magnet separator and method for separating, wherein the separator comprises a wet drum magnetic separator capable of treating, removing tramp metal from the full flow discharge of a grinding mill having a feed box which provides overflow capacity. Separation of magnetic particles of the mentioned dispersion is achieved by fixed magnets which are arranged at the inner side of a rotating drum. The mentioned document does not disclose any specific arrangement of the apparatus in respect of gravity.
EP 0 520 917 A1 discloses a method and apparatus for magnetic separation. The apparatus comprises a magnetic separator with fixed, low intensity magnets and a rotated drum, which is surrounded by a wall to get a long magnetic separation zone. The mentioned document does not disclose any arrangement of the apparatus in respect of gravity. Flushing along the separated magnetic particles is described, but no digging up the magnetic layer.
U.S. Pat. No. 3,489,280 discloses a magnetic separator having field shaping poles. The separator according to this document is a drum-like separator, wherein fixed magnets are arranged at the inside of the drum which is partly surrounded by a wall through the sobuilt channel the dispersion to be treated flows. Further magnets are arranged at the opposite side of this channel. The mentioned document does not disclose any arrangement of the apparatus in respect of gravity and no flushing of the magnetic separated fraction is documented.
SU 1240451 A1 discloses a separator for the separation of magnetic particles from a dispersion comprising these and nonmagnetic particles by a disk-like magnetic separator, comprising fixed magnets at the outside of the disks. A canal is formed at the inside of the disks and the dispersion to be treated flows through this canal. The magnets are located at alternating positions at both sides of the disk, so that the magnetic layer is dug up by running from one side of the canal to the other side. The magnetic fraction is washed out of the disk-like canal by a clean fluid, but no washing of the magnetic fraction is documented. The mentioned document does not disclose any arrangement of the apparatus in respect of gravity.
SU 1470341 A1 discloses a separator for separating magnetic particles from dispersants comprising these and nonmagnetic particles by a drum separator, wherein this drum separator comprises a long way along the drum in which a magnetic field is applied to the dispersion to be separated in order to increase yield and efficiency of magnetic separation.
WO 98/06500 discloses an apparatus and method for separating particles. This apparatus includes means for generating a rotating magnetic field such as a rotating magnetic drum. The canal through which the dispersion to be separated flows is in direct neighborhood to the magnets, wherein it is loop-like or linear. The separation is done by causing a rotation to the particles to be separated, what occurs to coarse particles, and to use this rotation as force to separate the magnetizable particles. It is not disclosed in said document that the whole reactor shall be arranged in respect to gravity in a way to improve separation of magnetic and nonmagnetic particles.
EP 1524038 A1 discloses a separator for separating magnetic particles from dispersants comprising these and nonmagnetic particles by a loop-like separator that is using magnetic forces to separate magnetic fraction assisted by centrifugal and gravity forces, wherein gravity forces are working across the flow direction due to the horizontal location of the loop and do not efficiently separate nonmagnetic constituents from the way of magnetic constituents. It is not disclosed to clean the magnetic fraction in any way.
The processes and apparatuses according to the prior art in general show the disadvantage that specific arrangements of the magnets are necessary in order to support the movement of the magnetic particles into at least one outlet in order to separate these magnetic particles from the dispersion. With these specific arrangements of the magnets, the maximal ranges of magnetic force cannot be exploited.
Furthermore, the processes known from the prior art generally have the disadvantage that only an unsatisfactory separating action is achieved since for example nonmagnetic constituents like gangue are also incorporated in the magnetic constituents adhering to the magnetic drum. These nonmagnetic constituents are in this way likewise separated off from the dispersion. The nonmagnetic constituents remain in the material of value after the magnetic constituents have been separated off and in the later work-up of the ore mineral, for example by smelting, leading to unfavorable space-time yields and thus to increased costs of the overall process. The use of a rotating magnetic roller does not, according to the prior art, make it possible for the proportion of nonmagnetic constituents to be effectively reduced.
It is therefore an object of the present invention to provide an apparatus and process for separating magnetic constituents from a preferably aqueous dispersion comprising these magnetic constituents and nonmagnetic constituents, in which a very small proportion of nonmagnetic constituents is separated off, for example by attachment to the magnetic constituents, together with the magnetic constituents comprising, for example, the desired ore mineral so as to increase the efficiency of the process.
Furthermore, it is advantageous if a very small proportion of nonmagnetic constituents is present in the fraction to be separated off, since, particularly in the separation of naturally occurring ores, the nonmagnetic constituents comprise essentially oxidic compounds which in a work-up of the ore mineral by smelting are obtained as slag and have an adverse effect on the smelting process. It is therefore also an object of the present invention to provide a process for separating naturally occurring ores so that a very small amount of slag is obtained in a subsequent smelting process.
The object of the present invention is to provide an apparatus and process for separating magnetic particles from a dispersion comprising these magnetic particles and nonmagnetic particles which give rise to an improvement in respect of yield and quality of the separated particles. In addition, an apparatus and process shall be provided with which it is possible to separate large amounts of material.
These objects are achieved by an apparatus for the separation of magnetic constituents from a dispersion comprising these magnetic constituents and nonmagnetic constituents, comprising at least one loop-like canal through which the dispersion flows having at least two inlets and at least two outlets, further comprising at least one magnet that is moveable alongside the canal, wherein the canal is arranged relative to gravity in a way that nonmagnetic constituents are assisted to go into the at least one first outlet by sedimentation and by the current of the dispersion and the magnetic constituents are forced into at least one second outlet by magnetic force against a current of flushing water.
The second outlet is preferably only an outlet for solid magnetic constituents, but preferably not for fluids like dispersion or flushing water with flushed non-magnetic constituents. The flushing water is added at the at least second outlet of the loop-like canal, where only magnetic constituents are moved by the at least one magnet. In a preferred embodiment, the application of a flushing water stream is performed to rearrange the magnetic fraction, in order to free therein stored nonmagnetic constituents.
The above-mentioned objects are further achieved by a process for the separation of magnetic constituents from a dispersion comprising these magnetic constituents and nonmagnetic constituents, wherein this dispersion flows through at least one loop-like canal having at least two inlets and at least two outlets, further comprising at least one magnet that is moveable alongside the canal, wherein the canal is arranged relative to gravity in a way that nonmagnetic constituents are assisted to go into at least one first outlet by sedimentation and by the current of the dispersion and magnetic constituents are forced into at least one second outlet by magnetic force against a current of flushing water.
The apparatus according to the present invention is explained in detail in the following.
The apparatus of the invention serves to separate magnetic constituents from an aqueous dispersion comprising these magnetic constituents and nonmagnetic constituents. The magnetic constituents can be originally magnetic by themselves or can be magnetized afterwards by the attachment of magnetic particles to non-magnetic particles.
According to the invention, the process can in general be employed for separating all magnetic constituents from nonmagnetic constituents that form dispersion, preferably in water.
In a preferred embodiment, the process of the invention serves to separate aqueous dispersions which originate from the work-up of naturally occurring ores.
In a further preferred embodiment of the process of the invention, the aqueous dispersion to be separated originates from a process for separating at least one first material from a mixture comprising this at least one first material and at least one second material, with the at least two materials being separated from one another by treating the mixture in aqueous dispersion with at least one magnetic particle, resulting in the at least one first material and the at least one magnetic particle agglomerating and thus forming the magnetic constituents of the aqueous dispersion and the at least one second material and the at least one magnetic particle not agglomerating so that the at least one second material preferably forms the nonmagnetic constituents of the aqueous dispersion.
The agglomeration of at least one first material and at least one magnetic particle to form the magnetic constituents in general occurs as a result of attractive interactions between these particles.
According to the invention, it is possible, for example, for said particles to agglomerate because the surface of the at least one first material is intrinsically hydrophobic or is hydrophobicized by treatment with at least one surface-active substance, if appropriate additionally. Since the magnetic particles likewise either themselves have a hydrophobic surface or are hydrophobicized, if appropriate additionally, said particles agglomerate as a result of the hydrophobic interactions. Since the at least one second material preferably has a hydrophilic surface, the magnetic particles and the at least one second material do not agglomerate. A process for formation these magnetic agglomerates is described, for example, in WO 2009/030669 A1. For all details of this process, reference is expressly made to this publication.
For the purposes of the present invention, “hydrophobic” means that the corresponding particle can have been hydrophobicized subsequently by treatment with the at least one surface-active substance. It is also possible for an intrinsically hydrophobic particle to be additionally hydrophobicized by treatment with the at least one surface-active substance.
“Hydrophobic” means, for the purposes of the present invention, that the surface of a corresponding “hydrophobic substance” or a “hydrophobicized substance” has a contact angle of >90° with water against air. “Hydrophilic” means, for the purposes of the present invention, that the surface of a corresponding “hydrophilic substance” has a contact angle of <90° with water against air.
The formation of magnetic agglomerates, i.e. the magnetic constituents which can be separated off by the process of the invention, can also occur via other attractive interactions, for example via the pH-dependent zeta potential of the corresponding surfaces, see, for example, the International publications WO 2009/010422 and WO 2009/065802. Further methods for attaching magnetic particles and particles to be separated off include application of bifunctional molecules, like for example described in WO2010/007075. Another method for attaching magnetic particles and particles to be separated off include application of molecules being hydrophobic or hydrophilic depending on the temperature, like for example described in WO2010/007157.
In a preferred embodiment of the process of the invention, the at least one first material which together with magnetic particles forms the magnetic constituents is at least one hydrophobic metal compound or coal and the at least one second material which forms the nonmagnetic constituents is preferably at least one hydrophilic metal compound.
The at least one first material is particularly preferably a metal compound selected from the group consisting of sulfidic ores, oxidic and/or carbonate-comprising ores, for example azurite [Cu3(CO3)2(OH)2] or malachite [Cu2—[(OH)2|CO3]]), or noble metals to which a surface-active compound can bind selectively to produce hydrophobic surface properties.
The at least one second material is particularly preferably a compound selected from the group consisting of oxidic and hydroxidic compounds, for example silicon dioxide SiO2, silicates, aluminosilicates, for example feldspars, for example albite Na(Si3Al)O8, mica, for example muscovite KAl2—[(OH,F)2AlSi3O10], garnets (Mg, Ca, FeII)3(Al,FeIII)2(SiO4)3, Al2O3, FeO(OH), FeCO3 and further related minerals and mixtures thereof. This at least one hydrophilic metal compound is itself nonmagnetic and also does not become magnetic by attachment of at least one magnetic particle. The at least one hydrophilic metal compound thus forms, in a preferred embodiment, the nonmagnetic constituents of the dispersion to be separated.
Examples of sulfidic ores which can be used according to the invention are, for example, selected from the group of copper ores, consisting of covellite CuS, chalcopyrite (copper pyrite) CuFeS2, bornite Cu5FeS4, chalcocite (copper glance) Cu2S and mixtures thereof, and also other sulfides such as molybdenum(IV) sulfide and pentlandite (NiFeS2).
Suitable oxidic metal compounds which can be used according to the invention are preferably selected from the group consisting of silicon dioxide SiO2, silicates, aluminosilicates, for example feldspars, for example albite Na(Si3Al)O8, mica, for example muscovite KAl2—[(OH,F)2AlSi3O10], garnets (Mg, Ca, FeII)3(Al, FeIII)2(SiO4)3 and further related minerals and mixtures thereof.
Accordingly, with the apparatus of the invention preferably ore mixtures which have been obtained from mine deposits and which have been treated with appropriate magnetic particles are treated.
In a preferred embodiment of the process of the invention, the mixture comprising at least one first material and at least one second material is present in the form of particles having a size of from 100 nm to 200 μm; see, for example, U.S. Pat. No. 5,051,199. Preferred ore mixtures have a content of sulfidic materials of at least 0.01% by weight, preferably 0.5% by weight and particularly preferably at least 3% by weight.
Examples of sulfidic minerals which are present in the mixtures which can be treated according to the invention are those mentioned above. In addition, sulfides of metals other than copper can also be present in the mixtures, for example sulfides of iron, lead, zinc or molybdenum, i.e. FeS/FeS2, PbS, ZnS or MoS2. Furthermore, oxidic compounds of metals and semimetals, for example silicates or borates, or other salts of metals and semimetals, for example phosphates, sulfates or oxides/hydroxides/carbonates and further salts, for example azurite [Cu3(CO3)2(OH)2], malachite [Cu2[(OH)2(CO3)]], barite (BaSO4), monazite ((La—Lu)PO4), can be present in the ore mixtures to be treated according to the invention. Further examples of the at least one first material which is separated off with the apparatus of the invention are noble metals, for example Au, Pt, Pd, Rh etc., which can be present in the native state, as alloy or in associated form.